Tires: Trailer tires, trailer tires, 5th wheels

Question
Are LT tires a suitable replacement for ST tires on travel trailers and 5th wheels?

Please explain tire reserve capacity.

Answer
Allan,

Yes, LT tires are suitable replacements for ST type tires – if the sizing is the same.

As you may have noticed, ST tires are listed as having more load carrying capacity than comparable LT tires.  This is partially because the speeds of ST tires are restricted to 65 mph, where  LT’s typically have a speed rating – and partially because ST tires are specified for trailer service and do not carry passengers.
And you probably noticed in other answers that I refer to “Reserve Capacity”.  This is unused capacity – the difference between the “rated” capacity and the full load as designed by the vehicle manufacturer.  
I think that trailer manufacturers not only should be using a 15% reserve capacity, but also need to do a better job of estimating what a fully loaded trailer actually weighs.